| PURPOSE: To describe the clinical characteristics and inherited pattern cataract associated in a large Chinese family with congenital inherited cataract and to identify the causative gene and mutation, single strand conformation polymophism (SSCP) analysis was used to screen GJA3 and GJA8 genes. METHODS:1. Investegation of clinical: An autosomal dominant cataract were identified in members of a large family of Han ethnicity living in China. Ophthalmological examinations included distance visual acuity, slit-lampexamination were performed and a medical history was taken.2. Blood samples were collected for 31 members of this family. Genomic DNA was extracted according to protocol provided by Roche Biochemical.3. Polymorphic markers on tdifferent genes ( CRYAA, CRYAB, CRYBA1/A3, CRYBB2,CRYGC,CRYGD, GJA8, GJA3, MIP , BFSP2 and HSF4) have been identified as causes of autosomal dominant congenital cataract (ADCC) wereselected .Linkage analysis was carried out using short tandem repeat polymorphism(STRP) in close proximity to genes and loci previously reported involving in human cataract.The marker were amplified by polymerase chain reaction(PCR).Fragments were separated by elecrophoresis through 6% denaturing polyacrylamid gels.Haplotypes were constructed manually according to the pattern of the bands on the gels by silver stain.Two-point linkage analysis lod scores were calculated.4. Single strand conformation polymophism (SSCP) analysis was used to screen CX46(GJA3)> CX50 (GJA8) genes, and the abnormal band were detected by 10% polyacrylamide gels stained by silver,followed by direct sequencing of observed electrophoretic shifts. The sequence of abnormal bands was compared with the normal sequences offered by GenBank.RESULTS:1. The cataracts were inherited as an autosomal dominant trait.2. All affected individuals displayed bilateral lens opacities, and pulverulentcataract cataract with variable severity.3. The LOD score of each selected markers ADCC in FANS family was negative.4. An abnormal band was found by SSCP in a patient, and sequence analysis proved a deletion of CA in none coding region of GJA3 gene. The phenotypes of these patients are not caused by mutation of GJA3 and GJA8 gene.CONCLUSIONS: No mutation was found .This known candidate genes associatedwith ADCC were excluded from FANS family. |
